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2023 Oʻahu Water Quality Report

Surfrider Foundation believes that all people should have access to water quality data. Our BWTF program empowers the local community to make informed decisions about where it is – or is not safe to swim.

2023 Overview

In 2023, volunteers sampled 24 sites every two weeks across Oʻahu. During this time period, 526 samples were collected, generating water quality information for recreational waters along the islandʻs North, South, East, and West shores. Samples were tested for the presence of enterococcus, a fecal bacteria that indicates the presence of human or animal waste in the water.  Elevated levels of enterococcus increase the likelihood that other pathogens that can make people sick may be present. Water is considered unsafe if levels exceed 130 enterococcus forming units/100mL. Sample collection and pollution level standards set by Hawaiʻi Department of Health (HDOH).  

Of the 24 sites regularly tested in 2023, seven exceeded health standards over 50% of the year.

blue water task force sample bottle

What did we find?

Of the 24 sites regularly tested in 2023, seven sites (Heʻeia Stream, Kaupuni Stream, Hakipuʻu Boat Ramp, Chocolates, Waiāhole Beach Park, Kuliʻouʻou Stream, Kahaluʻu) had 50% of their samples exceed state health standards. All of these sites showed similarly high bacteria levels in 2022. 

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BWTF volunteers are collecting water samples around the island every other Sunday. Pictured here is the Masterson ʻohana at Hakipuʻu boat ramp.

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Priority Sample Site: Kahaluʻu

Since 2018, Oʻahu BWTF monitoring has indicated chronically high bacteria levels at Kahaluʻu. In 2023, 89% of the samples collected at Kahaluʻu exceeded health standards. University of Hawaiʻi research indicates wastewater from cesspools is likely contributing to the high bacteria levels. Located at the mouth of a river, this site also receives high amounts of land-based runoff from its watershed.

Why are our coasts so polluted?

The BWTF chooses sites that are likely subject to higher levels of pollution to track pathogen levels and inform the local community. For example, Kahaluʻu, Hakipuʻu, and Waiāhole are all characterized by high concentrations of coastal cesspools, meaning that there is known wastewater contamination. The chronic pollution documented at these sites by the BWTF indicates the potential impact of sewage pollution in these areas.

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“Our data indicates that coastal cesspools are likely contributing to high bacteria readings in certain areas of the island,” said Dr. Dan Amato, Coordinator of the Oʻahu Blue Water Task Force. “In addition, large storms can contribute to elevated bacteria levels in coastal areas as flowing streams wash everything from upstream – pollutants, bacteria, nutrients, pesticides – into the ocean.”

Stop Sewage Pollution

As part of its recently launched STOP Sewage Pollution program, Surfrider Foundation encourages homeowners to  improve water quality by following these 8 simple steps:

  1. Convert your cesspool
  2. Share your knowledge about the impacts of cesspools on water quality
  3. Inspect and pump your septic tanks and cesspools regularly.
  4. Don’t use septic additives.
  5. Only flush the three P’s (pee, poop and toilet paper)
  6. Don’t pour cooking grease or oils down the drain.
  7. Conserve water inside your home.
  8. Soak up the rain and reduce runoff by directing roof downspouts into a rain barrel or vegetated area.

Community members are encouraged to check water quality results posted online before they head to the beach at Current and historic data are available.